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Background In implant dentistry, three-dimensional (3D) imaging can be realised by dental cone beam computed tomography (CBCT), offering volumetric data on jaw bones and teeth with relatively low radiation doses and costs. The latter may explain why the market has been steadily growing since the first dental CBCT system appeared two decades ago. More than 85 different CBCT devices are currently available and this exponential growth has created a gap between scientific evidence and existing CBCT machines. Indeed, research for one CBCT machine cannot be automatically applied to other systems. Methods Supported by a narrative review, recommendations for justified and optimized CBCT imaging in oral implant dentistry are provided. Results The huge range in dose and diagnostic image quality requires further optimization and justification prior to clinical use. Yet, indications in implant dentistry may go beyond diagnostics. In fact, the inherent 3D datasets may further allow surgical planning and transfer to surgery via 3D printing or navigation. Nonetheless, effective radiation doses of distinct dental CBCT machines and protocols may largely vary with equivalent doses ranging between 2 to 200 panoramic radiographs, even for similar indications. Likewise, such variation is also noticed for diagnostic image quality, which reveals a massive variability amongst CBCT technologies and exposure protocols. For anatomical model making, the so-called segmentation accuracy may reach up to 200 μm, but considering wide variations in machine performance, larger inaccuracies may apply. This also holds true for linear measures, with accuracies of 200 μm being feasible, while sometimes fivefold inaccuracy levels may be reached. Diagnostic image quality may also be dramatically hampered by patient factors, such as motion and metal artefacts. Apart from radiodiagnostic possibilities, CBCT may offer a huge therapeutic potential, related to surgical guides and further prosthetic rehabilitation. Those additional opportunities may surely clarify part of the success of using CBCT for presurgical implant planning and its transfer to surgery and prosthetic solutions. Conclusions Hence, dental CBCT could be justified for presurgical diagnosis, preoperative planning and peroperative transfer for oral implant rehabilitation, whilst striving for optimisation of CBCT based machine-dependent, patient-specific and indication-oriented variables.

To investigate potential correlations between objective CBCT image parameters and accuracy in endodontic working length determination ex vivo. Contrast-to-noise ratio (CNR) and spatial resolution (SR) as fundamental objective image parameters were examined using specific phantoms in seven different CBCT machines. Seven experienced observers were instructed and calibrated. The order of the CBCTs was randomized for each observer and observation. To assess intra-operator reproducibility, the procedure was repeated within six weeks with a randomized order of CBCT images. Multivariate analysis (MANOVA) did not reveal any influence of the combined image quality factors CNR and SR on measurement accuracy. Inter-operator reproducibility as assessed between the two observations was poor, with a mean intra-class correlation (ICC) of 0.48 (95%-CI  0.38, 0.59) for observation No. 1. and 0.40 (95%-CI 0.30, 0.51) for observation No. 2. Intra-operator reproducibility pooled over all observers between both observations was only moderate, with a mean ICC of 0.58 (95%-CI 0.52 to 0.64). Within the limitations of the study, objective image quality measures and exposure parameters seem not to have a significant influence on accuracy in determining endodontic root canal lengths in CBCT scans. The main factor of variance is the observer.

Background This prospective randomized clinical trial aimed to evaluate the immediate and short-term skeletal, dentoalveolar, and periodontal effects of rapid palatal expansion (RPE) and miniscrew-assisted RPE (MARPE) in adolescent and young adult patients. Methods This study followed a two-arm, parallel, randomized clinical trial design that recruited patients with transverse maxillary deficiency in a 1:1 allocation ratio. Forty patients (14 men and 26 women) requiring maxillary expansion were randomly allocated to the RPE (n = 20, age = 14.0 ± 4.5) or MARPE (n = 20, age = 14.1 ± 4.2) groups. The assignment was performed via computer-generated block randomization, with a block size of four. Upon identical (35 turns) amount of expansion, low-dose cone-beam computed tomography images were taken before treatment (T0), immediately after expansion (T1), and after a 3-month consolidation period (T2). The primary outcome of this study comprised the assessment of midpalatal suture separation. Secondary outcomes included, skeletal, dentoalveolar, and periodontal measurements, which were performed at each time point. Results The frequency of midpalatal suture separation was 90% (18/20) and 95% (19/20) for the RPE and MARPE groups, respectively. A greater increase in nasal width in the molar region (M-NW) and greater palatine foramen (GPF) was observed immediately after the expansion (T1-T0) and consolidation periods (T2-T0) in the MARPE group compared to the RPE group ( P  < 0.05). The MARPE and RPE groups showed similar dentoalveolar changes except for the maxillary width (PM-MW, M-MW). The MARPE group presented greater bilateral first premolar (PM-MW) and molar (M-MW) maxillary width in relation to the RPE group ( P  < 0.05). Through the expansion and consolidation periods (T2-T0), lesser buccal displacement of the anchor teeth was observed in the MARPE group (PM-BBPT, PM-PBPT, M-BBPT [mesial and distal roots], and M-PBPT)( P  < 0.05). Conclusions Midpalatal suture separation was observed in 90% and 95% of patients in the RPE and MARPE groups, respectively. Both RPE and MARPE groups exhibited significant triangular basal bone expansion and skeletal relapse during consolidation. Under identical amounts of expansion, the MARPE group showed lower decrease in the skeletal, dentoalveolar and periodontal variables after consolidation. The reinforcement of RPE with miniscrews contributes to the maintenance of the basal bone during consolidation period. Trial registration WHO Institutional Clinical Trials Registry Platform (IRB No. KCT0006871 / Registration date 27/12/2021).

Background In recent years, pediatric endodontics has witnessed various advances including use of rotary files in pulpectomy. This study aimed to comparatively evaluate taper, amount of dentin removal and instrumentation time of the pediatric rotary Kedo-S Square file, hand K-files and H-files in primary canines using cone beam computed tomography (CBCT). Methods 60 primary canines were randomly assigned into three groups; A1 Kedo-S-Square rotary file (group I), hand stainless steel K file (group II) and hand stainless steel H file (group III). Teeth were mounted in vinyl poly siloxane impression material templates to be scanned before and after instrumentation by CBCT scans using Ondemand 3D software. Shaping ability of the files were evaluated in terms of taper of the canal and amount of dentin remaining of each group. Instrumentation time was recorded using a digital stopwatch. Results Kedo-S Square removed a significantly less amount of dentin in both apical (P < 0.002) and coronal thirds (P < 0.014). Taper of the preparations showed significant differences as Kedo-S Square file showed good taper in maximum number of root canals, while maual K- and H-files showed poor taper in maximum number of root canals (P < 0.0001). Rotary Kedo-S Square files required less instrumentation time (P < 0.0001). Conclusion The use of rotary Kedo-S Square files resulted in better conservation of tooth structure, superior tapering ability and least instrumentation time compared to hand K- and H-files.

Purpose The development of on‐board cone‐beam computed tomography (CBCT) has led to improved target localization and evaluation of patient anatomical change throughout the course of radiation therapy. HyperSight, a newly developed on‐board CBCT platform by Varian, has been shown to improve image quality and HU fidelity relative to conventional CBCT. The purpose of this study is to benchmark the dose calculation accuracy of Varian's HyperSight cone‐beam computed tomography (CBCT) on the Halcyon platform relative to fan‐beam CT‐based dose calculations and to perform end‐to‐end testing of HyperSight CBCT‐only based treatment planning. Methods A HU to mass density curve was measured for the HyperSight CBCT system and implemented into the Eclipse treatment planning system. Following this, computational dosimetric analysis was performed between dose distributions calculated on CT simulation (CTsim) and HyperSight CBCT images on two anthropomorphic phantoms for pelvic and head and neck treatment sites. Additionally, an end‐to‐end test was carried out for a head and neck intensity modulated radiation therapy (IMRT) plan. Results The HU to mass density curves acquired on CTsim and HyperSight CBCT were similar (< 30 HU) for near‐water equivalent materials, but deviated for high‐density materials, with a maximum difference of 150 HU. For dose calculations, excellent agreement between dose calculations performed on CTsim and HyperSight CBCT phantom images was observed, where three‐dimensional gamma pass rates between the two dose distributions were observed to be ≥ $ \\ge $ 90% at 1%/1 mm (5% threshold). For the end‐to‐end test, absolute doses were verified to within 1% of ionization chamber measurements, while Delta4+ and portal dosimetry measurements yielded passing results (gamma pass rate ≥ $ \\ge $90%) down to 2%/2 mm criterion. Conclusion In this study, the accuracy of dose calculations performed on HyperSight CBCT was found to be within 1% of CTsim calculations for pelvic and head and neck treatment sites. End‐to‐end results using the RANDO anthropomorphic phantom indicate that HyperSight CBCT images are suitable for radiation treatment planning.

Background Different imaging techniques, such as multi-detector computed tomography (MDCT) scan and cone beam computed tomography(CBCT), are used to check the structure of the nose before rhinoplasty. This study aimed to evaluate the accuracy of two imaging techniques, MDCT scan, and CBCT, in diagnosing structural Variations in rhinoplasty for the first time. Methods This diagnostic accuracy study was conducted on 64 rhinoplasty candidates who complained of snoring and sleep apnea or had a positive result in the examination with Cottle’s maneuver or modified Cottle technique between February 2021 and October 2022 at 15- Khordad Hospital affiliated to Beheshti University of Medical Sciences. Before rhinoplasty, patients were randomly assigned to one of the CT and CBCT techniques with an equal ratio. Scans were assessed for the presence of Nasal septum deviation (NSD), Mucocele, Concha bullosa, and nasal septal spur by two independent radiologists. The findings of the two methods were evaluated with the results during rhinoplasty as the gold standard. Results NSD was the most common anatomical variation based on both imaging techniques. The accuracy of CBCT for diagnosing Nasal Septum Deviation and Mucocele was 80% and 75%, respectively. The sensitivity, specificity, and accuracy of CBCT in detecting Concha bullosa were 81.3% and 83.3%, respectively. The Kappa coefficient between CBCT and intraoperative findings for diagnosing NSD and Concha Bullosa was 0.76 and 0.73, respectively (p < 0.05). Conclusion CBCT can be considered a suitable method with high accuracy and quality to evaluate the anatomical variations before rhinoplasty.

This study was conducted to estimate the organ equivalent dose and effective imaging dose for four‐dimensional cone‐beam computed tomography (4D‐CBCT) using a Monte Carlo simulation, and to evaluate the excess absolute risk (EAR) of secondary cancer incidence. The EGSnrc/BEAMnrc were used to simulate the on‐board imager (OBI) from the TrueBeam linear accelerator. Specifically, the OBI was modeled based on the percent depth dose and the off‐center ratio was measured using a three‐dimensional (3D) water phantom. For clinical cases, 15 lung and liver cancer patients were simulated using the EGSnrc/DOSXYZnrc. The mean absorbed doses to the lung, stomach, bone marrow, esophagus, liver, thyroid, bone surface, skin, adrenal glands, gallbladder, heart, intestine, kidney, pancreas and spleen, were quantified using a treatment planning system, and the equivalent doses to each organ were calculated. Subsequently, the effective dose was calculated as the weighted sum of the equivalent dose, and the EAR of the secondary cancer incidence was determined for each organ with the use of the biologic effects of ionizing radiation (BEIR) VII model. The effective doses were 3.9 ± 0.5, 15.7 ± 2.0, and 7.3 ± 0.9 mSv, for the lung, and 4.2 ± 0.6, 16.7 ± 2.4, and 7.8 ± 1.1 mSv, for the liver in the respective cases of the 3D‐CBCT (thorax, pelvis) and 4D‐CBCT modes. The lung EARs for males and females were 7.3 and 10.7 cases per million person‐years, whereas the liver EARs were 9.9 and 4.5 cases per million person‐years. The EAR increased with increasing time since radiation exposure. In clinical studies, we should use 4D‐CBCT based on consideration of the effective dose and EAR of secondary cancer incidence.

Objectives The effect of head position on reproducibility of volumetric measurements on Cone‐beam computed tomography (CBCT) scans has not been evaluated before. Thus, this study aimed to assess the changes in linear and volumetric measurements on CBCT scans in different positions of the respective object. Materials and methods In this experimental study, 16 balls were placed in containers and underwent CBCT in neutral position and 8 different altered positions. The horizontal and vertical diameters of each ball were measured by OnDemand software while the volume of each ball was quantified by ITK‐Snap software. The reproducibility of linear and volumetric measurements in nine different positions was analyzed by the Cronbach's α. Paired t‐test was applied to analyze the difference in volumetric and linear measurements of the balls in the anterior and posterior halves of the scans in neutral position versus the upward and downward tilts, and right and left halves of the scans in neutral position versus the right and left tilts. Results The Cronbach's α was found to be .982 and .933 for volumetric and linear measurements, respectively, indicating high reproducibility of the measurements. No significant difference was noted in the mean linear measurements on CBCT scans at different positions compared with neutral position. In volumetric measurements, maximum difference between neutral and the other positions was less than 1%. Conclusions CBCT is a reliable modality for linear and volumetric measurements in different positions.

ObjectivesTo update the findings of a systematic review from the year 2016 on the evidence for the accuracy and potential benefits of cone beam computed tomography (CBCT) in periodontal diagnostics.Material and methodsA systematic literature search was performed and the criteria for PICO, PRISMA and risk of bias assessment were applied. Only clinical trials (> 10 patients) conducted in humans on periodontal bone loss, i.e. vertical and/or horizontal or furcation involvement, in CBCT compared with clinical and/or conventional radiographic measures were included.ResultsFrom 1152 articles identified, 11 case series on furcations and eight on vertical and/or horizontal bone loss were included. The studies showed moderate risk of bias and heterogeneous study designs. The agreement between non-surgical clinical or two-dimensional radiographic assessments of horizontal, vertical or interfurcal bone loss and CBCT measurements was analysed in 11 studies and was low in six studies with comparable study designs. A high accuracy (80–84%) of CBCT measurements compared with intra-surgical findings of furcation involvement was observed in four studies. Comparing CBCT with intra-surgical measurements of vertical or horizontal bone loss, an accuracy between 58 and 93% was found in four out of six studies. Three studies were analysed and indicated benefits of CBCT in decision making and/or a reduction of treatment costs and time in teeth of interest.ConclusionsThe findings provide additional evidence for the accuracy of CBCT in assessing periodontal bone loss.Clinical relevanceCBCT is an accurate diagnostic tool in periodontology, which needs to be carefully considered in certain situations.